End mills differ from drills in that they can also machine in a non-axial direction, and generally most if not all of their machining is in a non-axial direction.
Generally speaking, end mills can be theoretically divided into the following categories: insert-mills, solid end mills and replaceable milling heads.
Insert-mills are milling tools which comprise tool holders with pockets and replaceable inserts, typically indexable, configured to be mounted in the pockets. An advantage of insert-mills is that the replaceable inserts, which are made of comparatively expensive, harder, material constitutes a relatively small portion of the milling tool. The tool holders comprise a shank which is held securely by a collet or chuck during milling.
Unlike insert-mills which only require replacement of small inserts, solid end mills comprise integrally formed teeth and the entire solid end mill is replaced after it is worn. Solid end mills also comprise an integrally formed shank which is held securely by a collet or chuck during milling. Accordingly solid end mills utilize far more comparatively expensive material than insert-mills. Despite the comparatively higher cost, at least one advantage of solid end mills over insert-mills is that the solid end mill's single integrally formed body can be manufactured comparatively smaller allowing milling in relatively smaller locations.
Replaceable milling heads are similar to solid end mills in that they have integrally formed teeth. However they differ in that they have a shank-connector portion configured for attachment and removal from a shank. While solid end mills with their integrally formed shanks can, for example, be advantageous in terms of strength, vibration and simplified manufacture, a replaceable milling head's shank, which is held by a collet or chuck during milling, need not be replaced after the head is worn. Further, even though replaceable milling heads use more expensive material than insert mills they use less than solid end mills.
The subject matter of the present application is directed only to the latter category, namely replaceable milling heads.
More specifically, the present application is directed to heads configured for facing operations (i.e. configured with at least one axial cutting edge for a face milling operation, i.e. an operation carried out at the face of the head but in a non-axial direction). Preferred embodiments are directed also to heads configured only for facing operations, i.e. without using any radial cutting edges along the periphery of a cutting portion. Most preferred embodiments are directed specifically to heads having fast-feed tooth configurations, i.e. for machining only with axial cutting edges (stated differently, configured not to use even corner cutting edges, which are located between radial and axial cutting edges).